High-performance thin-layer chromatographic method for the simultaneous quantification of piperine, piperlongumine, and 6-shogaol in Trikatu Churna — an Ayurvedic formulation

Trikatu Churna is an important formulation in Ayurveda — the Traditional System of Indian Medicine. It consists of fine powders of fruits of Piper nigrum L., Piper longum L., and rhizomes of Zingiber officinale Roscoe in equal proportions. Piperine, present in both P. nigrum and P. longum, is considered to be responsible for the improvement of digestion and bioavailability enhancement of many medicaments. Gingerols and 6-shogaol are key chemical molecules in Z. officinale. Piperlongumine is present in P. longum fruits but absent in the fruits of P. nigrum. We report a validated high-performance thin-layer chromatography (HPTLC) method for the determination of piperine, piperlongumine, and 6-shogaol in these herbs and in Trikatu Churna. Piperine, piperlongumine, and 6-shogaol resolved well in n-hexane—ethyl acetate (8:2) on precoated silica gel 60 F254 plates. The absorption maxima for piperine, piperlongumine, and 6-shogaol were found to be 327, 272 and 235 nm, respectively. Linearity for the corresponding markers was observed between 0.1–0.5, 0.2–1.0, and 0.1–1.6 μg spot−1, respectively. The limit of detection (LOD) and limit of quantification (LOQ) were 28 and 100, 56 and 200, and 32 and 100 ng for piperine, piperlongumine, and 6-shogaol, respectively. Recovery experiments showed 99.6%, 99.5%, and 99.7% recoveries for piperine, piperlongumine, and 6-shogaol, respectively. P. nigrum fruits from Delhi and Ahmedabad had around 2.0% w/w piperine, while fruits of P. longum from these markets were analyzed for 0.8% and 0.6% w/w piperine. Piperlongumine was not found in both samples of P. nigrum, while the fruits of P. longum had 0.36% and 0.26% w/w piperlongumine. Z. officinale from Delhi had 0.19% w/w of 6-shogaol as against 0.16% w/w found in the sample from Ahmedabad. Plant materials procured from Delhi were employed for the preparation of Trikatu Churna which showed 96.5%, 95%, and 103% w/w of the expected values of piperine, piperlongumine, and 6-shogaol, respectively. The present method is simple, reproducible, and reliable which can be applied for the routine analysis of Trikatu Churna and its ingredients in polyherbal formulations.